It is common for a lamp to be plugged into a switched outlet so that, if the lamp switch is on, the lamp can be turned on and off by an outlet-controlling switch located remote from the outlet, typically at a door to a room in which the lamp is to be employed. This makes it possible to turn the lamp on from the doorway and to then turn the lamp off from the bedside or other location in which it is placed. This conventional arrangement leaves much to be desired. For example, if the lamp switch is left off, the lamp cannot be turned on by the wall switch and one may be faced with a potentially hazardous journey across a darkened room.
Electrical control devices designed to remedy the problems just described by making it possible in some circumstances to turn the load device on or off with a switch at one location even though the load device may have previously been placed in the opposite state with a switch at a second location have been disclosed. U.S. Pat. Nos. 2,477,862 issued 2 Aug. 1949 to Cook for HOUSE WIRING CIRCUITS; 3,418,489 issued 24 Dec. 1968 to Platzer, Jr. for SWITCHING CIRCUIT; 3,872,319 issued 18 Mar. 1975 to Platzer, Jr. for LAZY-MAN TYPE SWITCHING CIRCUIT; 4,383,186 issued 10 May 1983 to Liang for ELECTRICAL SWITCHING APPARATUS; 4,578,593 issued 25 March 1986 to Davidov for TWO-WAY ELECTRICAL CONTROL MODULE FOR A LAMP OUTLET disclose devices and systems of the just-described character.
The devices disclosed in the above-cited patents have a number of disadvantages such as complexity in installation and, more importantly, the inability to turn the controlled load device on (or off) in particular ones of the circumstances in which it would be highly desirable to do so. As a consequence, there is a continuing need for an electrical control device which can be readily installed between a controlled wall outlet and a load device and which allows the load device to be turned on and off from either of two locations in virtually any circumstance which may be encountered.